Hi OPT,
I started a thread in the brand discussion under Yamaha but I would also like your input. I have a 2001 yamaha that will not run, I changed the gas to fresh gas and when I spray carb and choke cleaner in the carb or air box it fires right up. I am a little stumped thinking maybe it was the fuel filter but I can not find one and when i disconnect the fuel line from the carb gas come right out of the line so I am thinking maybe dirty carb? if you could point me in the correct direction I would appreciate it.
Thanks I was going to send this to you in a private message but you do not accept them..

 

Pull the carb & clean the jets. Fuel delivery issue & clean the needle valve/seat

 

Sounds like you're working on a little bit of everything... On any machine there are basics to start out with. Spark,air supply,compression and fuel. I'd always do a basic check on spark,engine compression,valve clearance and mark them off the list and move on. You've checked spark,will run on carb cleaner which like ether is lighter than gas and usually will crank one.You say you have a good fuel supply,then probably could be the carb,but I'd always check the valve clearance,compression before you tear it apart.Just a process of elimination.

 

Okay and yes I always get myself into this kind of stuff. What should the compression be? And to check the valve clearance that is taking the top of the motor off correct like I had to do on my polaris?

 

Checking valve clearance on a Yamaha are like a lot of Hondas,just pull the valve cover plates/ caps. Actually easier on a lot of them compared to the Polaris 500. As to specs on valve clearance and compression,that's where the manuals come into play.Even just doing a google search can get you most specs on the model you have.

 

thanks OPT you have been a great help! I really appreciate it!! Yes I told him that he needs to buy a manual for it because the carb was apparently adjusted by his brother inlaw before he called me so I do not know where the idle screw should be set.. got to love helping friends... but thank you you for ur help I really do appreciate it. waiting on a rebuild kit for it and a new throttle cable looks like it was chewed on...

 

Brother in laws. I got one too..Most serve no worldly purpose but to screw things up.